Genesis theme hack - lost responsive layout

Hi, I have updated my LA, NYC, and San Diego subdomain themes to Genesis News Pro 3.02. Using mostly Firebug / Chrome Inspect, I hacked the CSS (using the Simple Custom CSS plugin) to get them looking like I want. LA and NYC look pretty good (IMHO). I went a few steps further with the San Diego site to narrow the header area, to increase the title area width to allow the title to display on one line. I also adjusted the size of the header right widget. I think I might have changed some of the padding or margins. I also did some other things with fonts, background, color, and alignment. Normally, when you look at the site on a PC, the title aligns left and the header right widget aligns right but on a mobile, it all centers perpendicularly. LA and NYC still work but now when I look at the SD site on the PC, it looks just like I want but when I check it out on a mobile screen, the title area no longer centers and it runs off screen. Also, the description, does not center and the header right widget does not center and aligns too far left. Can you look at it and see what's going on? What did I do that messed up the responsive layout? I had no luck finding the answer on the Studiopress / Genesis knowledge library and forums and their support does not give customization support (they used to be awesome but no more).